In the combustion of a fuel, such as coal, oil, peat, waste, etc., in a combustion plant, such as a power plant, a hot process gas is generated, such process gas containing, among other components, sulfur oxides, such as sulfur dioxide, SO2. Sulfur dioxide is an environmental pollutant. Hence, it is necessary to remove at least a portion of the sulfur dioxide from the process gas before the process gas can be released into the atmosphere.
U.S. Pat. No. 5,620,144 describes a wet scrubber which is operative for removing sulfur dioxide from a process gas. The wet scrubber comprises a vertical tower in which a number of atomization nozzles are arranged. The nozzles are arranged in at least one header arrangement. The header arrangement comprises a plurality of supply headers, each comprising a number of feeder lines. The feeder lines of one supply header are located directly atop the feeder lines of another supply header. A plurality of connectors are coupled to each of the feeder lines, each connector supporting at least one nozzle. The connectors and nozzles of one feeder line are staggered with respect to the connectors and nozzles of an adjacent feeder line located in close vertical proximity. The process gas passes vertically upwards through the wet scrubber tower and contacts the limestone absorption liquid droplets dispersed by the nozzles. The limestone absorption liquid droplets capture the sulfur dioxide of the process gas, and generates a solid end product.
A disadvantage of the wet scrubber of U.S. Pat. No. 5,620,144 is that the wet scrubber tower is a high piece of equipment, which makes it a costly investment and maintenance item. Furthermore, in combustion plants combusting various types and/or loads of fuels, it is difficult to control the sulfur dioxide removal efficiency to ensure suitable sulfur dioxide removal with minimal excesses. For example, when sulfur dioxide loads are high, the sulfur dioxide removal capacity must be high to ensure suitable sulfur dioxide removal. However, when sulfur dioxide loads are lower, the sulfur dioxide removal capacity may be lower ensuring suitable sulfur dioxide removal while minimizing excesses, e.g., energy consumption, equipment wear and the like.